Service Panels and Sub-Panels (Part 1)

A service panel is an electrical box which accepts incoming power from a utility and distributes it to various circuits within a building. It is also referred to as the “service”, the “breaker box” or the “fuse box.” Usually located near the electric meter, homeowners should know where it is and have a basic understanding of how it works.

Buildings are connected to the electrical grid via a “service drop” which can come in different sizes. A normal household service drop may be 100 amps or 200 amps, but commercial buildings have larger drops to match the electrical power needs of their equipment. Homeowners with older homes frequently ask us to upgrade their service from 100 to 200 amps as they add new circuits or electrical appliances to their homes.

The service drop comes through the electric meter so the company can charge for the amount of power you use. It comes into the service panel through a “main breaker” that allows a user to cut off all the power to all of the building with one switch. Below that breaker the power is distributed into a number circuits that go throughout the building. Each circuit has its own breaker so you can shut off the power to one area without affecting all the other circuits. Appliances like the water heater, air conditioner, stove, and dryer usually have their own dedicated circuit because they use so much energy.

Breakers work the same way a fuse works, shutting off the power when an unsafe condition exists. But unlike fuses, you can simply reset them without buying a new fuse. They also allow a person to work on a circuit safely since you can turn off the power before you begin the work.

Click the image on the left to see a short video by Greg Wells, Director of Operations at Frye Electric, who explains what homeowners need to know about resetting a breaker.

Remember that all work on the service panel beyond resetting a circuit breaker should be performed by a licensed electrician because of the danger to human life that exists. If a breaker trips repeatedly, leave it turned off and call an electrician to determine what is wrong on that circuit.

Part 2 of this post will explain sub-panels. Be sure to call us if you have any electrical questions. We’ll be glad to help or advise you.